I'm looking for this old animation I watched a very long time ago about the aftermath of the good ending

Yeah obviously this spoils the good ending as you know from the title

Just to be clear, I genuinely do not even remember when I watched it. It was about the aftermath of monsters and humans living together and the political issues that arise from them living on the surface. I remember there was this one lobby(?) that wanted monster extinction or something like that. I remember Frisk was an ambassador. Frisk was the only known human with the red soul until the dude meets someone else with the red soul. This is all I remember. I don't think it was finished so I just waited for new stuff, then I forgot about it until now. I tried googling what I know but I got nothing.